1. Field of the Invention
The present invention relates to a cooker with heating control system wherein its heater, such as a gas heater or electric heater, is automatically controlled with a high accuracy, thereby preventing boiling over of pan.
2. Description of the Prior Art
It is known that a stew cooking requires strong heating at the initial stage and, when the materials in the pan is about to boil the heating must be switched to a very low rate not to boil over, and such weak heating is continued for a long time. In order to proceed such cooking, person has been manually controlling the heater, and experiencing boiling over due to inadvertent forgetting of weakening the fire, and such manual handling is liable to waste of energy and difficult to carry out in ideal manner.
Hitherto, such a device as shown in FIG. 10(a) has been proposed that temperature of the food material 5 of a cooking pan 4 is measured by a sensor 6' and control circuit 10' issues a signal to control a valve 2 such as a proportional valve or a two step valve, thereby to control heat amount of the heater 3 basing on the temperature, which is measured by the sensor 6'. However, in the conventional device of FIG.10(a), the temperature sensor 6' is to be put in the cooking pan, and is not easy to use, and gives a feeling of insanitary or hazardous. Therefore, another device as shown in FIG.10(b) has been proposed to detect temperature at the bottom of a pan 4 by contacting a sensor 6 to the bottom of a pan 4; but this device has a problem that the detected temperature is different from the actual temperature of the contents and the trouble is that the difference varies depending on material, shape or size of the pan 4 and the amount of the food material 5.